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Sn IV Porphyrin Scaffolds for Axially Bonded Multiporphyrin Arrays: Synthesis and Structure Elucidation by NMR Studies
Author(s) -
Dvivedi Avanish,
Pareek Yogita,
Ravikanth Mangalampalli
Publication year - 2014
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201304344
Subject(s) - porphyrin , supramolecular chemistry , chemistry , proton nmr , fluorescence , crystallography , axial symmetry , stereochemistry , photochemistry , crystal structure , physics , structural engineering , quantum mechanics , engineering
A simple, one‐step, supramolecular strategy was adopted to synthesize Sn IV ‐porphyrin‐based axially bonded triads and higher oligomers by using meso ‐pyridyl Sn IV porphyrin, meso ‐hydroxyphenyl‐21,23‐dithiaporphyrin, and Ru II porphyrin as building blocks and employing complementary and non‐interfering Sn IV O and Ru II ⋅⋅⋅ N interactions. The multiporphyrin arrays are stable and robust and were purified by column chromatography. 1 H, 1 H– 1 H COSY and NOESY NMR spectroscopic studies were used to unequivocally deduce the molecular structures of Sn IV ‐porphyrin‐based triads and higher oligomers. Absorption and electrochemical studies indicated weak interaction among the different porphyrin units in triads and higher oligomers, in support of the supramolecular nature of the arrays. Steady‐state fluorescence studies on triads indicated the possibility of energy transfer in the singlet state from the basal Sn IV porphyrin to the axial 21,23‐dithiaporphyrin. However, the higher oligomers were weakly fluorescent due to the presence of heavy Ru II porphyrin unit(s), which quench the fluorescence of the Sn IV porphyrin and 21,23‐dithiaporphyrin units.